gcc/libgcov.c

/* Routines required for instrumenting a program.  */
/* Compile this one with gcc.  */
/* Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003  Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file into combinations with other programs,
and to distribute those combinations without any restriction coming
from the use of this file.  (The General Public License restrictions
do apply in other respects; for example, they cover modification of
the file, and distribution when not linked into a combine
executable.)

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

/* It is incorrect to include config.h here, because this file is being
   compiled for the target, and hence definitions concerning only the host
   do not apply.  */

#include "tconfig.h"
#include "tsystem.h"
#include "coretypes.h"
#include "tm.h"

#if defined(inhibit_libc)
#define IN_LIBGCOV (-1)
#else
#undef NULL /* Avoid errors if stdio.h and our stddef.h mismatch.  */
#include <stdio.h>
#define IN_LIBGCOV 1
#if defined(L_gcov)
#define GCOV_LINKAGE /* nothing */
#endif
#endif
#include "gcov-io.h"

#if defined(inhibit_libc)
/* If libc and its header files are not available, provide dummy functions.  */

#ifdef L_gcov
void __gcov_init (struct gcov_info *p __attribute__ ((unused))) {}
void __gcov_flush (void) {}
#endif

#ifdef L_gcov_merge_add
void __gcov_merge_add (gcov_type *counters  __attribute__ ((unused)),
		       unsigned n_counters __attribute__ ((unused))) {}
#endif

#ifdef L_gcov_merge_single
void __gcov_merge_single (gcov_type *counters  __attribute__ ((unused)),
			  unsigned n_counters __attribute__ ((unused))) {}
#endif

#ifdef L_gcov_merge_delta
void __gcov_merge_delta (gcov_type *counters  __attribute__ ((unused)),
			 unsigned n_counters __attribute__ ((unused))) {}
#endif

#else

#include <string.h>
#if GCOV_LOCKED
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#endif

#ifdef L_gcov
#include "gcov-io.c"

/* Chain of per-object gcov structures.  */
static struct gcov_info *gcov_list;

/* A program checksum allows us to distinguish program data for an
   object file included in multiple programs.  */
static gcov_unsigned_t gcov_crc32;

static int
gcov_version (struct gcov_info *ptr, gcov_unsigned_t version)
{
  if (version != GCOV_VERSION)
    {
      char v[4], e[4];

      GCOV_UNSIGNED2STRING (v, version);
      GCOV_UNSIGNED2STRING (e, GCOV_VERSION);
      
      fprintf (stderr,
	       "profiling:%s:Version mismatch - expected %.4s got %.4s\n",
	       ptr->filename, e, v);
      return 0;
    }
  return 1;
}

/* Dump the coverage counts. We merge with existing counts when
   possible, to avoid growing the .da files ad infinitum. We use this
   program's checksum to make sure we only accumulate whole program
   statistics to the correct summary. An object file might be embedded
   in two separate programs, and we must keep the two program
   summaries separate.  */

static void
gcov_exit (void)
{
  struct gcov_info *gi_ptr;
  struct gcov_summary this_program;
  struct gcov_summary all;
  struct gcov_ctr_summary *cs_ptr;
  const struct gcov_ctr_info *ci_ptr;
  unsigned t_ix;
  gcov_unsigned_t c_num;

  memset (&all, 0, sizeof (all));
  /* Find the totals for this execution.  */
  memset (&this_program, 0, sizeof (this_program));
  for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next)
    {
      ci_ptr = gi_ptr->counts;
      for (t_ix = 0; t_ix < GCOV_COUNTERS_SUMMABLE; t_ix++)
	{
	  if (!((1 << t_ix) & gi_ptr->ctr_mask))
	    continue;

	  cs_ptr = &this_program.ctrs[t_ix];
	  cs_ptr->num += ci_ptr->num;
	  for (c_num = 0; c_num < ci_ptr->num; c_num++)
	    {
      	      cs_ptr->sum_all += ci_ptr->values[c_num];
	      if (cs_ptr->run_max < ci_ptr->values[c_num])
		cs_ptr->run_max = ci_ptr->values[c_num];
	    }
	  ci_ptr++;
	}
    }

  /* Now merge each file.  */
  for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next)
    {
      struct gcov_summary this_object;
      struct gcov_summary object, program;
      gcov_type *values[GCOV_COUNTERS];
      const struct gcov_fn_info *fi_ptr;
      unsigned fi_stride;
      unsigned c_ix, f_ix, n_counts;
      struct gcov_ctr_summary *cs_obj, *cs_tobj, *cs_prg, *cs_tprg, *cs_all;
      int error = 0;
      gcov_unsigned_t tag, length;
      gcov_position_t summary_pos = 0;

      memset (&this_object, 0, sizeof (this_object));
      memset (&object, 0, sizeof (object));
      
      /* Totals for this object file.  */
      ci_ptr = gi_ptr->counts;
      for (t_ix = 0; t_ix < GCOV_COUNTERS_SUMMABLE; t_ix++)
	{
	  if (!((1 << t_ix) & gi_ptr->ctr_mask))
	    continue;

	  cs_ptr = &this_object.ctrs[t_ix];
	  cs_ptr->num += ci_ptr->num;
	  for (c_num = 0; c_num < ci_ptr->num; c_num++)
	    {
	      cs_ptr->sum_all += ci_ptr->values[c_num];
	      if (cs_ptr->run_max < ci_ptr->values[c_num])
		cs_ptr->run_max = ci_ptr->values[c_num];
	    }

	  ci_ptr++;
	}

      c_ix = 0;
      for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
	if ((1 << t_ix) & gi_ptr->ctr_mask)
	  {
	    values[c_ix] = gi_ptr->counts[c_ix].values;
	    c_ix++;
	  }

      /* Calculate the function_info stride. This depends on the
	 number of counter types being measured.  */
      fi_stride = sizeof (struct gcov_fn_info) + c_ix * sizeof (unsigned);
      if (__alignof__ (struct gcov_fn_info) > sizeof (unsigned))
	{
	  fi_stride += __alignof__ (struct gcov_fn_info) - 1;
	  fi_stride &= ~(__alignof__ (struct gcov_fn_info) - 1);
	}
      
      if (!gcov_open (gi_ptr->filename))
	{
	  fprintf (stderr, "profiling:%s:Cannot open\n", gi_ptr->filename);
	  continue;
	}

      tag = gcov_read_unsigned ();
      if (tag)
	{
	  /* Merge data from file.  */
	  if (tag != GCOV_DATA_MAGIC)
	    {
	      fprintf (stderr, "profiling:%s:Not a gcov data file\n",
		       gi_ptr->filename);
	    read_fatal:;
	      gcov_close ();
	      continue;
	    }
	  length = gcov_read_unsigned ();
	  if (!gcov_version (gi_ptr, length))
	    goto read_fatal;

	  length = gcov_read_unsigned ();
	  if (length != gi_ptr->stamp)
	    {
	      /* Read from a different compilation. Overwrite the
		 file.  */
	      gcov_truncate ();
	      goto rewrite;
	    }
	  
	  /* Merge execution counts for each function.  */
	  for (f_ix = 0; f_ix < gi_ptr->n_functions; f_ix++)
	    {
	      fi_ptr = (const struct gcov_fn_info *)
		      ((const char *) gi_ptr->functions + f_ix * fi_stride);
	      tag = gcov_read_unsigned ();
	      length = gcov_read_unsigned ();

	      /* Check function.  */
	      if (tag != GCOV_TAG_FUNCTION
		  || length != GCOV_TAG_FUNCTION_LENGTH
		  || gcov_read_unsigned () != fi_ptr->ident
		  || gcov_read_unsigned () != fi_ptr->checksum)
		{
		read_mismatch:;
		  fprintf (stderr, "profiling:%s:Merge mismatch for %s\n",
			   gi_ptr->filename,
			   f_ix + 1 ? "function" : "summaries");
		  goto read_fatal;
		}

	      c_ix = 0;
	      for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
		{
		  gcov_merge_fn merge;

		  if (!((1 << t_ix) & gi_ptr->ctr_mask))
		    continue;
		  
		  n_counts = fi_ptr->n_ctrs[c_ix];
		  merge = gi_ptr->counts[c_ix].merge;
		    
		  tag = gcov_read_unsigned ();
		  length = gcov_read_unsigned ();
		  if (tag != GCOV_TAG_FOR_COUNTER (t_ix)
		      || length != GCOV_TAG_COUNTER_LENGTH (n_counts))
		    goto read_mismatch;
		  (*merge) (values[c_ix], n_counts);
		  values[c_ix] += n_counts;
		  c_ix++;
		}
	      if ((error = gcov_is_error ()))
		goto read_error;
	    }

	  f_ix = ~0u;
	  /* Check program & object summary */
	  while (1)
	    {
	      gcov_position_t base = gcov_position ();
	      int is_program;
	      
	      tag = gcov_read_unsigned ();
	      if (!tag)
		break;
	      length = gcov_read_unsigned ();
	      is_program = tag == GCOV_TAG_PROGRAM_SUMMARY;
	      if (length != GCOV_TAG_SUMMARY_LENGTH
		  || (!is_program && tag != GCOV_TAG_OBJECT_SUMMARY))
		goto read_mismatch;
	      gcov_read_summary (is_program ? &program : &object);
	      if ((error = gcov_is_error ()))
		goto read_error;
	      if (is_program && program.checksum == gcov_crc32)
		{
		  summary_pos = base;
		  goto rewrite;
		}
	    }
	}
      
      if (!gcov_is_eof ())
 	{
 	read_error:;
 	  fprintf (stderr, error < 0 ? "profiling:%s:Overflow merging\n"
 		   : "profiling:%s:Error merging\n", gi_ptr->filename);
 	  goto read_fatal;
 	}
    rewrite:;
      gcov_rewrite ();
      if (!summary_pos)
	memset (&program, 0, sizeof (program));

      /* Merge the summaries.  */
      f_ix = ~0u;
      for (t_ix = 0; t_ix < GCOV_COUNTERS_SUMMABLE; t_ix++)
	{
	  cs_obj = &object.ctrs[t_ix];
	  cs_tobj = &this_object.ctrs[t_ix];
	  cs_prg = &program.ctrs[t_ix];
	  cs_tprg = &this_program.ctrs[t_ix];
	  cs_all = &all.ctrs[t_ix];

	  if ((1 << t_ix) & gi_ptr->ctr_mask)
	    {
	      if (!cs_obj->runs++)
		cs_obj->num = cs_tobj->num;
	      else if (cs_obj->num != cs_tobj->num)
		goto read_mismatch;
	      cs_obj->sum_all += cs_tobj->sum_all;
	      if (cs_obj->run_max < cs_tobj->run_max)
		cs_obj->run_max = cs_tobj->run_max;
	      cs_obj->sum_max += cs_tobj->run_max;
	      
	      if (!cs_prg->runs++)
		cs_prg->num = cs_tprg->num;
	      else if (cs_prg->num != cs_tprg->num)
		goto read_mismatch;
	      cs_prg->sum_all += cs_tprg->sum_all;
	      if (cs_prg->run_max < cs_tprg->run_max)
		cs_prg->run_max = cs_tprg->run_max;
	      cs_prg->sum_max += cs_tprg->run_max;
	    }
	  else if (cs_obj->num || cs_prg->num)
	    goto read_mismatch;
	  
	  if (!cs_all->runs && cs_prg->runs)
	    memcpy (cs_all, cs_prg, sizeof (*cs_all));
	  else if (!all.checksum
		   && (!GCOV_LOCKED || cs_all->runs == cs_prg->runs)
		   && memcmp (cs_all, cs_prg, sizeof (*cs_all)))
	    {
	      fprintf (stderr, "profiling:%s:Invocation mismatch - some data files may have been removed%s",
		       gi_ptr->filename, GCOV_LOCKED
		       ? "" : " or concurrent update without locking support");
	      all.checksum = ~0u;
	    }
	}
      
      c_ix = 0;
      for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
	if ((1 << t_ix) & gi_ptr->ctr_mask)
	  {
	    values[c_ix] = gi_ptr->counts[c_ix].values;
	    c_ix++;
	  }

      program.checksum = gcov_crc32;
      
      /* Write out the data.  */
      gcov_write_tag_length (GCOV_DATA_MAGIC, GCOV_VERSION);
      gcov_write_unsigned (gi_ptr->stamp);
      
      /* Write execution counts for each function.  */
      for (f_ix = 0; f_ix < gi_ptr->n_functions; f_ix++)
	{
	  fi_ptr = (const struct gcov_fn_info *)
		  ((const char *) gi_ptr->functions + f_ix * fi_stride);

	  /* Announce function.  */
	  gcov_write_tag_length (GCOV_TAG_FUNCTION, GCOV_TAG_FUNCTION_LENGTH);
	  gcov_write_unsigned (fi_ptr->ident);
	  gcov_write_unsigned (fi_ptr->checksum);

	  c_ix = 0;
	  for (t_ix = 0; t_ix < GCOV_COUNTERS; t_ix++)
	    {
	      gcov_type *c_ptr;

	      if (!((1 << t_ix) & gi_ptr->ctr_mask))
		continue;

	      n_counts = fi_ptr->n_ctrs[c_ix];
		    
	      gcov_write_tag_length (GCOV_TAG_FOR_COUNTER (t_ix),
				     GCOV_TAG_COUNTER_LENGTH (n_counts));
	      c_ptr = values[c_ix];
	      while (n_counts--)
		gcov_write_counter (*c_ptr++);

	      values[c_ix] = c_ptr;
	      c_ix++;
	    }
	}

      /* Object file summary.  */
      gcov_write_summary (GCOV_TAG_OBJECT_SUMMARY, &object);

      /* Generate whole program statistics.  */
      gcov_seek (summary_pos);
      gcov_write_summary (GCOV_TAG_PROGRAM_SUMMARY, &program);
      if ((error = gcov_close ()))
	  fprintf (stderr, error  < 0 ?
		   "profiling:%s:Overflow writing\n" :
		   "profiling:%s:Error writing\n",
		   gi_ptr->filename);
    }
}

/* Add a new object file onto the bb chain.  Invoked automatically
   when running an object file's global ctors.  */

void
__gcov_init (struct gcov_info *info)
{
  if (!info->version)
    return;
  if (gcov_version (info, info->version))
    {
      const char *ptr = info->filename;
      gcov_unsigned_t crc32 = gcov_crc32;
  
      do
	{
	  unsigned ix;
	  gcov_unsigned_t value = *ptr << 24;

	  for (ix = 8; ix--; value <<= 1)
	    {
	      gcov_unsigned_t feedback;

	      feedback = (value ^ crc32) & 0x80000000 ? 0x04c11db7 : 0;
	      crc32 <<= 1;
	      crc32 ^= feedback;
	    }
	}
      while (*ptr++);
      
      gcov_crc32 = crc32;
      
      if (!gcov_list)
	atexit (gcov_exit);
      
      info->next = gcov_list;
      gcov_list = info;
    }
  info->version = 0;
}

/* Called before fork or exec - write out profile information gathered so
   far and reset it to zero.  This avoids duplication or loss of the
   profile information gathered so far.  */

void
__gcov_flush (void)
{
  const struct gcov_info *gi_ptr;

  gcov_exit ();
  for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next)
    {
      unsigned t_ix;
      const struct gcov_ctr_info *ci_ptr;
      
      for (t_ix = 0, ci_ptr = gi_ptr->counts; t_ix != GCOV_COUNTERS; t_ix++)
	if ((1 << t_ix) & gi_ptr->ctr_mask)
	  {
	    memset (ci_ptr->values, 0, sizeof (gcov_type) * ci_ptr->num);
	    ci_ptr++;
	  }
    }
}

#endif /* L_gcov */

#ifdef L_gcov_merge_add
/* The profile merging function that just adds the counters.  It is given
   an array COUNTERS of N_COUNTERS old counters and it reads the same number
   of counters from the gcov file.  */
void
__gcov_merge_add (gcov_type *counters, unsigned n_counters)
{
  for (; n_counters; counters++, n_counters--)
    *counters += gcov_read_counter ();
}
#endif /* L_gcov_merge_add */

#ifdef L_gcov_merge_single
/* The profile merging function for choosing the most common value.
   It is given an array COUNTERS of N_COUNTERS old counters and it
   reads the same number of counters from the gcov file.  The counters
   are split into 3-tuples where the members of the tuple have
   meanings:
   
   -- the stored candidate on the most common value of the measured entity
   -- counter
   -- total number of evaluations of the value  */
void
__gcov_merge_single (gcov_type *counters, unsigned n_counters)
{
  unsigned i, n_measures;
  gcov_type value, counter, all;

  GCOV_CHECK (!(n_counters % 3));
  n_measures = n_counters / 3;
  for (i = 0; i < n_measures; i++, counters += 3)
    {
      value = gcov_read_counter ();
      counter = gcov_read_counter ();
      all = gcov_read_counter ();

      if (counters[0] == value)
	counters[1] += counter;
      else if (counter > counters[1])
	{
	  counters[0] = value;
	  counters[1] = counter - counters[1];
	}
      else
	counters[1] -= counter;
      counters[2] += all;
    }
}
#endif /* L_gcov_merge_single */

#ifdef L_gcov_merge_delta
/* The profile merging function for choosing the most common
   difference between two consecutive evaluations of the value.  It is
   given an array COUNTERS of N_COUNTERS old counters and it reads the
   same number of counters from the gcov file.  The counters are split
   into 4-tuples where the members of the tuple have meanings:
   
   -- the last value of the measured entity
   -- the stored candidate on the most common difference
   -- counter
   -- total number of evaluations of the value  */
void
__gcov_merge_delta (gcov_type *counters, unsigned n_counters)
{
  unsigned i, n_measures;
  gcov_type last, value, counter, all;

  GCOV_CHECK (!(n_counters % 4));
  n_measures = n_counters / 4;
  for (i = 0; i < n_measures; i++, counters += 4)
    {
      last = gcov_read_counter ();
      value = gcov_read_counter ();
      counter = gcov_read_counter ();
      all = gcov_read_counter ();

      if (counters[1] == value)
	counters[2] += counter;
      else if (counter > counters[2])
	{
	  counters[1] = value;
	  counters[2] = counter - counters[2];
	}
      else
	counters[2] -= counter;
      counters[3] += all;
    }
}
#endif /* L_gcov_merge_delta */

#endif /* inhibit_libc */